drm/sun4i: hdmi: Fix usage of TMDS clock

plaes · mripard · commit 5e1bc251cebc · 2019-01-22T10:16:22.000+01:00
Although TMDS clock is required for HDMI to properly function, nobody called clk_prepare_enable(). This fixes reference counting issues and makes sure clock is running when it needs to be running. Due to TDMS clock being parent clock for DDC clock, TDMS clock was turned on/off for each EDID probe, causing spurious failures for certain HDMI/DVI screens. Fixes: 9c56810 ("drm/sun4i: Add HDMI support") Signed-off-by: Priit Laes <priit.laes@paf.com> [Maxime: Moved the TMDS clock enable earlier] Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190122073232.7240-1-plaes@plaes.org
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
@@ -92,6 +92,8 @@ static void sun4i_hdmi_disable(struct drm_encoder *encoder)
 	val = readl(hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
 	val &= ~SUN4I_HDMI_VID_CTRL_ENABLE;
 	writel(val, hdmi->base + SUN4I_HDMI_VID_CTRL_REG);
+
+	clk_disable_unprepare(hdmi->tmds_clk);
 }
 
 static void sun4i_hdmi_enable(struct drm_encoder *encoder)
@@ -102,6 +104,8 @@ static void sun4i_hdmi_enable(struct drm_encoder *encoder)
 
 	DRM_DEBUG_DRIVER("Enabling the HDMI Output\n");
 
+	clk_prepare_enable(hdmi->tmds_clk);
+
 	sun4i_hdmi_setup_avi_infoframes(hdmi, mode);
 	val |= SUN4I_HDMI_PKT_CTRL_TYPE(0, SUN4I_HDMI_PKT_AVI);
 	val |= SUN4I_HDMI_PKT_CTRL_TYPE(1, SUN4I_HDMI_PKT_END);
